Tony Blair has told the nation that giving in to the firefighters' 40% pay claim would be unrealistic and would have "dire" consequences for the economy.

In a televised statement, seen as a direct intervention in the dispute by the prime minister, he said the only way forward was through negotiation.

Fire Brigades Union (FBU) leader Andy Gilchrist said Mr Blair was right in saying a negotiated settlement was the only way forward and said he was prepared to negotiate.

Pay linked to modernisation is the only way this can be resolved

Tony Blair

The prime minister was forced by the Conservatives to make an emergency statement in the Commons about the fire strike on Monday afternoon, during which he repeated his tough stance.

He told MPs: "If the government were to yield to this claim... the consequences across the whole of the public sector would be huge.

"Nurses, soldiers - after all many of them manning the appliances at the moment are on pay far below that of the firefighters - teachers, police officers would also be seeking similar claims."

And in a move that would be likely to enrage firefighters, Downing Street said it might consider "lockouts" if fire strikes continued.

The Prime Minister's Official Spokesman said: "That is something that will have to be looked at in future."

The prime minister himself had earlier warned a pay claim of 40% would undermine the economy and the cost would be a 30% increase in income tax, higher mortgage and interest rates and unemployment.

In his televised statement, he said he accepted firefighters did a vital job, but other public sector workers carried out an equally important job and were paid far less than firefighters.

Mr Blair described the firefighter strikes as "wrong and dangerous".

"There are limits to the money available, so pay linked to modernisation is the only way this can be resolved," he said.

Mr Blair: Deal must not risk economic stability

"Both sides know it means getting back round the negotiating table sooner or later. Let's hope it's sooner."

Six people have died in house fires since the latest eight-day walk-out began.

Mr Blair denied the government had deliberately "engineered" the dispute with firefighters, as has been suggested in certain quarters.

He also said the government could not write a blank cheque authorising a 16% pay deal - proposed by the fire union and employers last Friday - which was not funded through modernisation.

He said the deal would have consisted of four pay rises over 12 months with the unions only agreeing to "talk about modernisation".

The reforms proposed by Sir George Bain and supported by the government were not "unreasonable", he added.

He said a 16% pay rise would cost the government an extra �4bn if applied across the whole of the local authority sector and an extra �16bn if applied across the public sector as a whole.

Mr Gilchrist, responding to Mr Blair's speech, said firefighters had spent years modernising and would continue to modernise the service, but he said the government-commissioned Bain report was a "cuts agenda".

He said: "The government needs to make in the next few days, a vital decision.

The work of the armed forces has been praised

"Do we or do we not want to live in a society which places a real value on public service?

"It's said of course our rise will have dire consequences for the economy, so what of his own rise - the prime minister - or indeed his cabinet or his members of parliament colleagues?"

Tory leader Iain Duncan Smith agreed Cabinet ministers had failed to speak with "consistency and clarity" on the issue, sending out mixed messages instead.

But he the government should not give into inflationary pay demands.

But said the government should not give into inflationary pay demands.

Following on from Mr Blair's emergency statement, Deputy Prime Minister John Prescott will make a Commons statement on the dispute on Tuesday.